it's for you
The person calling on the phone wants to talk to you. Hey Peter, it's for you—it's one of the guys from accounting. A: "Was that the phone ringing?" B: "Yeah, and it's for you—here you go."
It's for you.
This telephone call is for you. Henry: Hello? Fred: Hello. Is Bill there? Henry: Hey, Bill! It's for you. Bill: Thanks. Hello? "It's for you," said Mary, handing the telephone receiver to Sally.